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Posts tagged “Emydidae

Wood Turtles — Aquatic & Terrestrial, Depending on the Season

8-6-13 wood turtle2 046The Wood Turtle’s (Glyptemys insculpta) common name comes from the resemblance of each segment of its top shell, or carapace, to the cross-section of a tree complete with radiating growth rings. Unlike other turtles that favor either land or water, wood turtles reside in both aquatic and terrestrial habitats. They require streams and rivers for spring mating, feeding and winter hibernation, but also require terrestrial habitats for summer egg-laying and foraging. In slow moving streams and rivers (see photo insert) they feed on fish and insects. On land, usually within 300 yards of a stream, they forage for snails, slugs, berries and mushrooms. Wood Turtles are known for stomping their feet on the ground in order to presumably mimic the vibrations of rain. Earthworms then come to the surface, and the turtle snaps them up.

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Turtle Eyes

6-16-13 painted turtle eye line 226When a turtle moves its head, its eye moves to compensate, so that its eye remains in the same position – parallel to the horizon or pond surface — no matter what position the turtle’s head is in. This type of eye stabilization is called vestibulo-ocular reflex (VOR). Humans have a very similar reflex, but it’s easier to detect on a Painted Turtle (pictured) because of its dark eye line. A turtle’s eye structure is stabilized to the horizon, which makes sense, as turtles spend their life close to the ground and/or the pond surface, and this reflex enables it to align its vision horizontally in order to find food, a mate and predators.

Baby Painted Turtles Migrating to Ponds

5-20-13 baby painted turtlesIn May, at the very same time that adult painted turtles are laying their eggs, some of last year’s young turtles are migrating from their nest site to ponds or rivers. Painted turtle eggs actually hatch in late summer, with the young turtles remaining inside the nest cavity for varying amounts of time. Here in New England, in the northern part of their range, they often overwinter in their nest and emerge the following spring.

Wood Turtles Laying Eggs

5-10-13 wood turtle burying eggs IMG_3717Congratulations on correctly identifying the trails as being made by turtles! Even though you did not have the benefit of knowing their width, many of you took a stab at the naming the species of turtle that made them. Hats off to Jason, who correctly identified them as wood turtle trails, especially as it is relatively early in the season for them to be laying eggs.

Two female wood turtles (so-called because of the resemblance of their top shell, or carapace, to wood), were on their way out of a shallow wetland to dig into soft sand about 6” deep and lay their (4 – 18, usually 8 or 9) eggs. The size of the footprints, tail drag and 7-inch flattened shell path help to identify these trails as those of wood turtles. Although you can follow the tracks and see exactly where the trails end, it would be hard to detect that excavation and egg-laying has taken place at these sites, as the holes have been filled in and smoothed over with the turtles’ bottom shells, or plastrons. Predators with a good sense of smell, such as foxes, raccoons and skunks, however, have very little trouble locating turtle nests. Research shows that 85% of wood turtle eggs and hatchlings are lost to predation. The wood turtle population is in decline in the northeast in part due to human development which not only decreases wood turtle habitat and increases the number of people collecting these turtles, but also increases the number of predators. (The wood turtle in the photograph has just laid her eggs and smoothed over the nest site in front of her head by walking backwards over it while pressing her plastron to the ground.)